At the end of my work flow I would save to a file my new completed image into a master file where I would return when I needed to to print the image - the only thing I needed to do was sharpen and print. My original image with no work done was kept in the as shot file from where it came.
Just the same in LR, only more convenient :
-
The adjustments to your "master file" are automatically saved after each edit, in the catalog by default, and a copy of the adjustments is also written in an XMP file if you choose so (catalog preferences, metadata, write changes in XMP).
- The original file is left untouched,
- You can always export a jpeg for emailing, or print one copy (sharpening and resizing handled very well by LR), or upload images in a web gallery...
As feppe, if you take the time to sit a few hours and watch the tutorial having LR at hand to practice what you learn, it should be much clearer.